esp8266/modnetwork: Allow to get ESSID of AP that STA is connected to.
esp8266/modnetwork: Allow to get ESSID of AP that STA is connected to.

This patch enables iface.config('essid') to work for both AP and STA
interfaces.

(cherry picked from commit d8fdb77ac91b578d851b873a004b530b42313cf1)

adafruit/circuitpython,adafruit/circuitpython,adafruit/micropython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/micropython,adafruit/micropython,adafruit/micropython,adafruit/micropython,adafruit/circuitpython